Number Worlds: Visual and Experimental Access to Elementary Number Theory Concepts. - Nathalie Sinclair; Rina Zazkis; Peter Liljedahl (Int. J. Comput. Math. Learn., 2003)

A coloured window on pre-service teachers' conceptions of rational numbers. - Nathalie Sinclair; Peter Liljedahl; Rina Zazkis (Int. J. Comput. Math. Learn., 2006)